Quarter-elliptical springs make the Bronco rock
If you've seen one Bronco on the rocks, you've seen them all, right? That's what most people assume until they spy Tom Boyd cruise over fullsized boulders with his '71 half-cab Bronco and never lift a tire off the ground. Horse manure, you say? We spent the day with Tom on the famed Sledgehammer Trail and can attest that his Pony keeps its tires planted on terra firma, no matter what.
The key is in a completely redesigned rear suspension combined with a thoughtfully modified front suspension. The rear sits on quarter-elliptical leaf springs. Greg Grosset from Total Performance in Santee, California, designed the rear suspension and committed Tom to the project by ripping all the old stuff from the frame only weeks before the Tierra Del Sol Safari in California earlier this year. Greg constructed a four-link suspension with Heim joints to position the 9-inch rearend. After a few iterations, he found that using a limiting strap attached to the center of the rear axle kept the driveshaft from overextending but didn't limit droop at the tires. The design of the four-link and quarter-elliptical springs allows for plenty of droop and exerts pressure on the drooping tire to add to its traction.
The front suspension was scheduled for revamping, but it has worked so well with the Wild Horses 4-inch lift springs that Tom is now considering extending the radius arms, using Heim joints at the attaching points, and calling it good enough. After seeing the Bronco on the trail, we'd have to agree.
The rest of the Bronco is a mix of well-designed innovations such as a Total Performance custom dashboard, a rollcage with protected mounts for mirrors and auxiliary driving lights, a front bumper with rock rollers, a swing-out dual gas can and spare-tire carrier, and B.C. Broncos 1/4-inch-thick rock skis.